Heart valves, such as the mitral, tricuspid, aortic, and pulmonary valves, are sometimes damaged by disease or by aging, resulting in problems with the proper functioning of the valve. Heart valve problems generally take one of two forms: stenosis in which a valve does not open completely or the opening is too small, resulting in restricted blood flow; or insufficiency in which blood leaks backward across a valve when it should be closed.
Heart valve replacement via surgical procedure is performed for patients suffering from valve regurgitation or stenotic calcification of the leaflets. Conventionally, the vast majority of valve replacements entail a full sternotomy and placing the patient on cardiopulmonary bypass.
Traditional open surgery inflicts significant patient trauma and discomfort, requires extensive recuperation times, and may result in life-threatening complications.
To address these concerns, efforts have been made to perform cardiac valve replacements using minimally-invasive techniques. In these methods, laparoscopic instruments are employed to make small openings through the patient's ribs to provide access to the heart. While considerable effort has been devoted to such techniques, widespread acceptance has been limited by the clinician's ability to access only certain regions of the heart using laparoscopic instruments.
Still other efforts have been focused upon percutaneous transcatheter (or transluminal) delivery of replacement cardiac valves to solve the problems presented by traditional open surgery and minimally-invasive surgical methods. In such methods, a prosthetic heart valve, also known as a valve prosthesis, a valve stent, or a stented valve, is compacted for delivery in a catheter and then advanced, for example through an opening in the femoral artery and through the descending aorta to the heart, where the prosthesis is then deployed in the valve annulus (e.g., the aortic valve annulus).
Various types and configurations of prosthetic heart valves are used in percutaneous valve procedures to replace diseased natural human heart valves. The actual shape and configuration of any particular prosthetic heart valve is dependent to some extent upon the valve being replaced (i.e., mitral valve, tricuspid valve, aortic valve, or pulmonary valve). In general, prosthetic heart valve designs attempt to replicate the function of the valve being replaced and thus will include valve leaflet-like structures used with either bioprostheses or mechanical heart valve prostheses. In order to prepare such a prosthetic heart valve for percutaneous implantation, one type of prosthetic heart valve can include a stent frame made of a self-expanding material. With these systems, the prosthetic heart valve is crimped down to a desired size and held in that compressed state within a capsule or sheath of a delivery catheter, for example. Loading the prosthetic heart valve into the capsule of the delivery catheter is generally accomplished manually and can be difficult and time consuming. In an example, the delivery catheter may include a plurality of tethers, with a looped end of each tether threaded or woven through a respective portion of the frame of the prosthetic heart valve. Each looped end is looped around a tether post of the delivery catheter. Once the looped end of each of the plurality of tethers are looped through the frame of the prosthetic heart valve and the respective tether post, the looped ends must be held in place as the delivery catheter is manipulated such that tether posts, and releasably coupled prosthetic heart valve is loaded into the capsule and retained therein. However, manually holding the looped ends of the plurality of tethers for proper retraction and loading into the delivery catheter is difficult and time consuming.
Accordingly, there is a need for systems, tools and methods for quickly and easily loading a prosthetic heart valve into a delivery catheter.